The invention relates to a micromechanical acceleration sensor manufactured from a first semiconductor wafer and a second semiconductor wafer, where on the first semiconductor wafer at least a first electrode is provided to create a variable capacitance and the second semiconductor wafer has a movable second electrode, and where on the first semiconductor wafer there is a microelectronic evaluation unit.
A capacitive state-of-the-art acceleration sensor is known, for instance, from the patent publication U.S. Pat. No. 4,483,194. The sensor described there has a tongue structure made by means of the so-called "bulk micromechanical" method. The change in its capacitance, resulting from an acceleration force acting on the sensor, is evaluated with a separate circuit arrangement.
This sensor has the disadvantage that in the manufacture of the sensor a process is used whereby the wafer used must be completely etched through from its reverse side. Owing to the given crystallographic etching angle, additional expensive silicon area is therefore required. Furthermore, the sensor element must be packaged with two more wafers in order to be hermetically sealed.